It is known that treatment of some diseases requires frequent injections of medicine, for example, daily injections of insulin in the case of certain forms of diabetes. The patients who suffer from such diseases must resort to the care of physicians, nurses or perform the necessary injections themselves. The use of syringes, even of the discardable type, is a nuisance to the user. Further, the handling and preparation necessary for performing the injections with such syringes further increase the unpleasantnesses inherent in such treatments.
Devices have already been proposed seeking to avoid a part of the drawbacks mentioned above during treatments comprising repeated injections of medical substances or the like. In this regard reference is made to French patent No. 2 348 709 and U.S. Pat. No. 4,345,595.
In both of these documents, an injection needle forms the end of a syringe with a mobile piston, the amplitude of the movement of the piston determining the volume injected. If the volume injected is to be determined with precision, mechanical control means become complex, heavy and expensive so that the device is no longer suitable for use in frequent treatments.